Pipeline fails when there are multiple pipelines/jobs executed

Using self managed gitlab with self managed gitlab runner on v15.7.5. Pipeline runs when a single pipeline is run on a single gitlab runner shell executor. However, scheduled pipelines causes pipelines to fail. (Certain jobs might pass). Runner timeout is set to 1 hour. Expected behaviour is that the jobs will be in queue and waiting for the shell executor gitlab runner to be available before executing the job. But it fails during cloning in a job with the error message as shown in attached image.

Your GitLab Runner version is 13.8.0 as visible in the log. It should match the version of GitLab instance.

From the log it seems you have network issues and Runner is not able to clone the repository, because of connection timeout. I would start troubleshooting there.

Will update gitlab runner version to match gitlab server. Thanks for your reply.

From gitlab runner able to telnet gitlab server. This error only occurs intermittently when there are multiple pipelines running concurrently. Not sure if it is a network issue?

You can use concurrent parameter in GitLab Runner config.toml to configure how many jobs can run concurrently. If you are ok with just 1 you can avoid the issue.

Otherwise try to simulate by running multiple git clone manually on shell. Maybe you could replicate.